The present invention relates to an electronic timepiece, and more particularly to an electronic timepiece having a powersave mode.
Electronic timepieces that switch to a powersave mode in which power consumption is reduced, for example, by stopping the drive of the second hand requiring high power consumption when a predetermined condition is satisfied are widely used. In particular, a widely known technique is an electronic timepiece having power generating means, such as solar cells, and a power generation sensing function in which power save operates when power is not generated. An appropriate document in which this technique is disclosed is Japanese Patent Publication No. Hei 5-60075, filed by the present applicant.
In this Japanese Patent Publication is disclosed a timepiece having what is called a powersave function where the light striking the timepiece is sensed by an illuminance sensing circuit (power generation sensing circuit), where the hands are stopped to reduce power consumption and only the time is counted by the circuit when it is dark, and the current time is restored when it is bright.
However, the solar timepiece is constrained in terms of timepiece design since the solar cells for receiving light and generating power have a dark appearance. Recent solar timepieces use a light transmitting dial with a white ceramic plate and the solar cells are positioned underneath (inside the timepiece) the dial. Thus, timepieces with superior designs have been commercialized and with solar cells that are difficult to see from the outside. However, the light transmittance differs depending on the type of dial, such as the ceramic plate thickness, material, and color, and when the same timepiece module is used, the brightness of the ambient light at which the power save is entered differs depending on the product type since the sensing level of the illuminance sensing circuit is fixed. In other words, when the illuminance sensing level is set to match a dial having a high light transmittance, and a product uses a dial having a low light transmittance, the generated energy of the solar cells underneath the dial having a low light transmittance is smaller compared to when a dial having a high light transmittance is used so that the power save is entered even though the ambient light is sufficiently bright.
Furthermore, in the case where the power consumption for driving the second hand differs depending on the timepiece and the generated energy at which the power save is entered is fixed, when the generated energy that is slightly larger than the generated energy at which the power save is entered is supplied for long period, the energy stored in the storage means, such as a secondary cell, gradually decreases depending on the type of timepiece, resulting in the possibility that the timepiece may stop.
It is an object of the present invention to solve the above-mentioned problems and provide an electronic timepiece in which a predetermined value can be adjusted in the power-save mode switching means for switching to the power-save mode when the level of the energy generated by the power generating means is less than or equal to the predetermined value.
In order to achieve the above-mentioned object, the present invention, in an electronic timepiece having power save means for switching to a power-save mode that reduces power consumption when a predetermined condition is satisfied, comprises power generating means, storage means for storing energy generated by the power generating means, power save-mode switching means for switching to the power-save mode when the level of energy generated by the power generating means is less than or equal to a predetermined value, and adjusting means for setting the predetermined value for each different timepiece or type of timepiece having differences in a ability to generate energy under an ambient power generating condition.
Furthermore, it is preferable for the predetermined value to be greater than or equal to a predetermined generated energy capable of driving the timepiece.
Furthermore, it is preferable for the predetermined value to be greater than or equal to a predetermined generated energy capable of driving the second hand.
Furthermore, it is preferable for the adjusting means to comprise resistors and switches for selecting the resistors.
Furthermore, it is preferable to provide setting means for controlling the adjusting means and to have a setting mode to allow operation of the setting means.
Furthermore, it is preferable for the state of the switches selecting the resistors of the adjusting means to select a maximum resistance until the setting mode is first allowed.
Furthermore, it is preferable for the setting means to be user setting means for controlling the adjusting means by user input.
Furthermore, in a state where light of predetermined illuminance is supplied to the timepiece, it is preferable for the setting mode to control the adjusting means, and it is more preferable for the predetermined illuminance to be 10 lux or lower and even more preferable for the predetermined illuminance to be 5 lux or lower.
Furthermore, it is preferable for the setting mode to complete operation by a change in output of the power-save mode switching means.
Furthermore, it is preferable to have informing means for operating at completion of operation of the setting mode.
Furthermore, it is preferable to enable the setting mode to be entered by an external switch operation.
Furthermore, it is preferable to enable the setting mode to be entered by a contract-free external magnetic field control.
Furthermore, it is preferable to enable the setting mode to be entered through one mode of userselectable added functions.